Tomas Prior

Prediction of intrapartum fetal compromise using the cerebroumbilical ratio: a prospective observational study

OBJECTIVE To investigate the use of the fetal cerebroumbilical ratio to predict intrapartum compromise in appropriately grown fetuses. STUDY DESIGN A prospective observational study set at Queen Charlottes and Chelsea hospital, London, UK. Fetal biometry and Doppler resistance indices were measured in 400 women immediately before established labor. Labor was then managed according to local protocols and guidelines, and intrapartum and neonatal outcome details recorded. RESULTS Infants delivered by cesarean section for fetal compromise had significantly lower cerebroumbilical ratios than those born by spontaneous vaginal delivery (1.52 vs 1.82, P ≤ .001). Infants with a cerebroumbilical ratio <10th percentile were 6 times more likely to be delivered by cesarean section for fetal compromise than those with a cerebroumbilical ratio ≥10th percentile (odds ratio, 6.1; 95% confidence interval, 3.03-12.75). A cerebroumbilical ratio >90th percentile appears protective of cesarean section for fetal compromise (negative predictive value 100%). CONCLUSION The fetal cerebroumbilical ratio can identify fetuses at high and low risk of a subsequent diagnosis of intrapartum compromise, and may be used to risk stratify pregnancies before labor.

Prediction of fetal compromise in labor

OBJECTIVE: The majority of intrapartum fetal hypoxia occurs in uncomplicated pregnancies. Current intrapartum monitoring techniques have not resulted in a reduction in the incidence of cerebral palsy in term neonates. We report the development of a composite risk score to allow risk stratification of normal pregnancies before labor. METHODS: Six hundred one women were recruited to this prospective observational study. All women underwent an ultrasound examination before active labor, during which fetal biometry and fetal Doppler flow resistance indices were measured. A composite risk score, amalgamating data from the umbilical artery, middle cerebral artery, and umbilical vein, was then developed and correlated with intrapartum outcomes. RESULTS: In cases with the highest composite risk scores, the incidence of fetal compromise (the primary outcome) was 80.0% compared with just 15.3% in cases with the lowest risk scores (relative risk 5.2, 95% confidence interval 2.7–10.1). These cases were also at increased risk of cesarean delivery (53.3% compared with 3.4%, P<.001) and of developing a fetal heart rate pattern considered pathologic by National Institute for Health and Clinical Excellence criteria (P=.003). No significant variation in Apgar scores or umbilical artery pH was observed. CONCLUSION: Intrapartum fetal compromise remains a significant global health issue. The composite risk score reported here can identify fetuses at both high risk and low risk of a subsequent diagnosis of intrapartum fetal compromise. This may enable more judicious use of current intrapartum fetal monitoring techniques, which are hampered by low specificity. LEVEL OF EVIDENCE: II

Are fetuses that fail to achieve their growth potential at increased risk of intrapartum compromise

The true growth potential of a fetus is difficult to predict but recently a new definition, independent of fetal weight, using cerebroplacental (cerebro‐umbilical) ratio (CPR) < 0.6765 multiples of the median (MoM), was reported. We applied this definition to a cohort of low‐risk pregnancies recruited prospectively to determine if fetuses with CPR < 0.6765 are at increased risk of developing signs of intrapartum fetal compromise.

Sex specific differences in fetal middle cerebral artery and umbilical venous Doppler.

Background The incidence of several adverse pregnancy outcomes including fetal growth restriction are higher in pregnancies where the fetus is male, leading to suggestions that placental insufficiency is more common in these fetuses. Placental insufficiency associated with fetal growth restriction may be identified by multi-vessel Doppler assessment, but little evidence exists regarding sex specific differences in these Doppler indices or placental function. This study aims to investigate sex specific differences in fetal and placental perfusion and to correlate these changes with intra-partum outcome. Methods and Findings This is a prospective cohort study. We measured Doppler indices of 388 term pregnancies immediately prior to the onset of active labour (≤3 cm dilatation). Fetal sex was unknown at the time of the ultrasound assessment. Information from the ultrasound scan was not made available to clinical staff. Case notes and electronic records were reviewed following delivery. We report significantly lower Middle Cerebral artery pulsatility index (1.34 vs. 1.43, p = 0.004), Middle Cerebral artery peak velocity (53.47 cm/s vs. 58.10 cm/s, p = <0.001), and Umbilical venous flow/kg (56 ml/min/kg vs. 61 ml/min/kg, p = 0.02) in male fetuses. These differences however, were not associated with significant differences in intra-partum outcome. Conclusion Sex specific differences in feto-placental perfusion indices exist. Whilst the physiological relevance of these is currently unknown, the identification of these differences adds to our knowledge of the physiology of male and female fetuses in utero. A number of disease processes have now been shown to have an association with changes in fetal haemodynamics in-utero, as well as having a sex bias, making further investigation of the sex specific differences present during fetal life important. Whilst the clinical application of these findings is currently limited, the results from this study do provide further insight into the gender specific circulatory differences present in the fetal period.

Changes in the maternal cytokine profile in pregnancies complicated by fetal growth restriction

Fetal growth restriction (FGR) is an important and poorly understood condition of pregnancy, which results in significant fetal, neonatal and long‐term morbidity and mortality. The aetiology of FGR is unknown and is likely to result from sub‐optimal placental implantation and feto‐maternal immunological interaction. The diagnostic criteria for FGR vary between studies, and the condition often occurs with preeclampsia (PET). We present a review of studies of maternal cytokines in FGR and compare these with studies of Small for Gestational Age and PET pregnancies.

Early procedure-related complications of fetal blood sampling and intrauterine transfusion for fetal anemia.

Objective. To review the procedure‐related complication rates following fetal blood sampling and intrauterine red cell transfusion for anaemic fetuses at a single tertiary center. Design. A retrospective study of 114 intrauterine transfusions. Setting. A single tertiary referral fetal medicine center at Queen Charlottes and Chelsea Hospital, Imperial College London, London, UK. Sample. All cases (114) undergoing fetal blood sampling and intrauterine transfusion between January 2003 and May 2010. Methods. Early procedure‐related complications (severe fetal bradycardia requiring either abandonment of the procedure or emergency delivery, fetal death, preterm labor or rupture of membranes) were investigated by review of computerized records and individual chart review. Main outcome measures. Live birth rate, perinatal mortality, procedure‐related fetal bradycardia, preterm labor and procedure‐related spontaneous rupture of membranes. Results. The majority of cases (77.8%) were due to red cell alloimmunization, with anti‐D being the commonest cause. The live birth rate was 93.5%, with a procedure‐related fetal death rate of 0.9%. The preterm labor rate (<37 weeks’ gestation) was 3.5% only occurring in patients undergoing multiple (>3) fetal transfusions. Complications in this series did not appear to be increased the earlier the gestation at which the first transfusion took place. Conclusions. Despite a reduction in the number of cases requiring intrauterine therapy for fetal anemia, contemporary outcomes appear to be good if not improving. It is important that the experience required to manage these cases should be concentrated in fewer centers to maximize good perinatal outcome.

Maternal and perinatal outcomes following peripartum hysterectomy from a single tertiary centre

We investigated the indications for and maternal and perinatal outcomes following peripartum hysterectomy in a single large tertiary centre.

Gender specific intrapartum and neonatal outcomes for term babies.

OBJECTIVE The purpose of this study is to document the gender specific intrapartum and neonatal outcomes in term, singleton, appropriately grown babies. STUDY DESIGN De-identified, routinely collected data of all women meeting inclusion criteria between 2001 and 2011 were examined (n=9223). Inclusion criteria were public (non-insured), primiparous women who had delivered singleton, appropriately grown babies at term. In this retrospective cohort study, we estimated 95% confidence intervals. Outcomes measured were maternal demographics, mode of delivery, birthweight, APGAR score, cord blood acidemia, respiratory distress, any resuscitation requirement, nursery admission and stillbirth rates. RESULTS The sex ratio of male babies was 1.05:1 (4718 males; 4505 females, p=0.85). Male babies were more likely to be delivered by instrumental (p=0.004) or caesarean (p<0.001). Birthweight was found to be a significant influencing factor on mode of delivery. Even after adjusting for birthweight, male babies were more likely to be delivered by instrumental delivery (OR 1.24, p<0.001), as well as by emergency caesarean for failure to progress (OR 1.24, p=0.04) and fetal distress (OR 1.38, p<0.001). Male babies, despite having greater birthweights than female babies (p<0.001), were more likely to have lower APGAR scores at 5 min (p=0.004), require neonatal resuscitation (p<0.001), develop respiratory distress (p=0.005) and require nursery admission (p<0.001). No statistical difference between male and female babies was found for cord blood acidemia (p=0.58) or stillbirth (p=0.49). CONCLUSION This large cohort study demonstrates that term, appropriately grown male babies in primiparous pregnancies fare more poorly in the intrapartum and neonatal periods than female babies. Even when birthweight was accounted for, male babies still required higher rates of intervention in the intrapartum and neonatal periods. This suggests gender may play an independent role in influencing pregnancy outcomes, although the underlying contributing physiology is not definitively established. The gender of the baby perhaps should be considered when counselling parents in the antepartum period.

Expert review – identification of intra-partum fetal compromise

Whilst most cases of cerebral palsy occur as a consequence of an ante-natal insult, a significant proportion, particularly in the term fetus, are attributable to intra-partum hypoxia. Intra-partum monitoring using continuous fetal heart rate assessment has led to an increased incidence of operative delivery without a concurrent reduction in the incidence of cerebral palsy. Despite this, birth asphyxia remains the strongest and most consistent risk factor for cerebral palsy in term infants. This review evaluates current intra-partum monitoring techniques as well as alternative approaches aimed at better identification of the fetus at risk of compromise in labour.

Are babies that fail to reach their genetic growth potential at increased risk of intra-partum fetal compromise?

The true growth potential of a fetus is difficult to predict but recently a new definition, independent of fetal weight, using cerebroplacental (cerebro‐umbilical) ratio (CPR) < 0.6765 multiples of the median (MoM), was reported. We applied this definition to a cohort of low‐risk pregnancies recruited prospectively to determine if fetuses with CPR < 0.6765 are at increased risk of developing signs of intrapartum fetal compromise.